Declaration

Overview

Use a volume view to present the user with a slider control for setting the system audio output volume, and a button for choosing the audio output route. When first displayed, the slider’s position reflects the current system audio output volume. As the user drags the slider, the changes update the volume view. If the user presses the device volume buttons while sound is playing, the slider moves to reflect the new volume.

If there is an Apple TV or other AirPlay-enabled device in range, the route button allows the user to choose it. If there is only one audio output route available, the route button is not displayed.

Important

You can't change the volume or choose a route with this class while testing in the Simulator. These abilities only work on a device.

Use this class by embedding an instance of it in your view hierarchy. The following code snippet assumes you have placed an instance of the UIView class on a view using Interface Builder, sizing and positioning it as desired to contain the volume view. Point to the UIView instance with an outlet variable—named, in the case of this example, mpVolumeViewParentView. You would typically place code like that shown in Listing 1 in your viewDidLoad method.

Customizing the Volume Slider’s Appearance

The volume slider is a UISlider object. Sliders are always displayed as horizontal bars and an indicator, or thumb, notes the current value of the slider and can be moved by the user to change the setting.

Slider controls draw the volume slider track using two distinct images, which are customizable. The region between the thumb and the end of the track associated with the slider’s minimum value is drawn using the minimum volume slider image. The region between the thumb and the end of the track associated with the slider’s maximum value is drawn using the maximum volume slider image. Assigning different images to each state lets you customize the appearance of the slider when it is enabled, disabled, highlighted, and so on.

You can also customize the volume thumb image for the slider.

Note

The volume slider control provides a set of default images for both the track and thumb. If you do not specify any custom images, those images are used automatically.